Borehole tool heat transfer altering system and method, and method of heating borehole fluid

ABSTRACT

A borehole tool heat transfer altering system includes, a borehole tool, and a thermoelectric material in operable communication with the borehole tool configured to alter heat transfer between the borehole tool and an environment surrounding the borehole tool.

BACKGROUND

Tubular systems employed in earth formation borehole applications such as the downhole completion and carbon dioxide sequestration industries, for example, often employ mechanical devices such as, motors and pumps, as well as electrical components, such as, circuits and computers for a variety of purposes. Operating temperatures of such devices can be determined by temperatures of environments surrounding the devices and by energy consumed by the devices themselves in the process of normal operation. Operating devices at temperatures outside of recommended temperature ranges can detrimentally affect performance of the device including efficiency and durability, for example. Systems and methods that aid in altering temperature of such devices are well received in the art.

BRIEF DESCRIPTION

Disclosed herein is a borehole tool heat transfer altering system. The system includes, a borehole tool, and a thermoelectric material in operable communication with the borehole tool configured to alter heat transfer between the borehole tool and an environment surrounding the borehole tool.

Further disclosed herein is a method of altering heat transfer to a borehole tool. The method includes electrically energizing thermoelectric material in operable communication with a borehole tool and an environment, and altering heat transfer between the borehole tool and the environment.

Further disclosed herein is a method of heating borehole fluids. The method includes, electrically energizing a thermoelectric material, and increasing transfer of heat from a borehole tool to borehole fluids through the thermoelectric material.

Further disclosed herein is a method of increasing efficiency of a borehole pumping operation. The method includes, increasing heat transfer between a borehole tool and fluid within a wellbore, decreasing viscosity of the fluid, and pumping the fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 depicts an end view of a borehole tool heat transfer altering system disclosed herein;

FIG. 2 depicts a cross sectioned side view of the borehole tool heat transfer altering system of FIG. 1 taken at arrows 2-2;

FIG. 3 depicts a partially sectioned perspective view of a portion of a layered assembly employed in the construction of the borehole tool heat transfer altering system of FIG. 1;

FIG. 4 depicts a sequential representation of steps employed during an embodiment of a construction process for the borehole tool heat transfer altering system of FIG. 1;

FIG. 5 depicts a schematical view of a completion employing an embodiment of a borehole tool heat transfer altering system disclosed herein;

FIG. 6 depicts a schematical view of another completion employing an embodiment of a borehole tool heat transfer altering system disclosed herein; and

FIG. 7 depicts a schematical view of another completion employing an embodiment of a borehole tool heat transfer altering system disclosed herein.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

Referring to FIGS. 1-3, an embodiment of a borehole tool heat transfer altering system is disclosed generally at 10. The borehole tool heat transfer altering system 10 works on the principle of the Seebeck effect to convert electricity supplied to a thermoelectric material directly into temperature differences across the thermoelectric material, and uses no moving parts in the process. The borehole tool heat transfer altering system 10 includes, a layered assembly 14, conformed to a surface 18 (an outer surface in this embodiment) of a tubular 22. The layered assembly 14 has a core 26 of thermoelectric material 30, with conductors 34, 38, shown herein as layers of conductive material, electrically bonded to opposing surfaces 44, 48 of the thermoelectric material 30. A protector 50 including layers 54, 58 of electrically insulative material electrically insulates the conductors 34, 38 while fluidically isolating the conductors 34, 38 and the thermoelectric material 30 from an environment that the borehole tool heat transfer altering system 10 is submerged within. Terminals 64, 68 sealably penetrate the protector 50 and are electrically connected to the conductors 34, 38 respectively. The foregoing structure creates a temperature gradient radially across the thermoelectric material 30 when an electrical potential is applied to the conductors 34, 38. Connection to the terminals 64, 68 allow the electrical energy from a source (not shown) to be supplied to the conductors 34, 38.

Referring to FIG. 3, the layered assembly 14 is shown in a flat position with portions of each layer removed for illustrative purposes. The thermoelectric material 30 that constitutes the core 26 can be made of solid composite materials as described in the paper, “Thermoelectric Behavior of Segregated-Network Polymer Nanocomposites,” James C. Grunlan, et al.; Nano Letters, 2008 Vol. 8, No. 12, pgs. 4428-4432, incorporated herein by reference in its entirety. Although this thermoelectric material includes both polymeric particles and carbon nano-particles, alternate thermoelectric materials may be employed as long as they meet the requirements outlined herein. The thermoelectric material 30 can be processed by methods, such as, casting or extruding, for example, to form a sheet of the core 26. After which, in this embodiment, the conductors 34, 38 are electrically and optionally mechanically bonded to the surfaces 44, 48 respectively. The conductors can be made of conductive materials, such as, copper, gold, silver or aluminum, for example. These materials can be bonded to the core 26 in one of several ways including, vapor deposition, soldering and brazing, for example. The insulative layers 54, 58 are bonded to the conductors 34, 38 respectively. The insulative layers 54, 48 may be sheets of insulative material such as polymeric, elastomeric or glass, for example. The insulative layers 54, 58 can be bonded to the conductors 34, 48 through chemical and mechanical means such as bonding with an adhesive agent, for example. Portions 74, 78 of the layers 54, 58 that extend beyond the core 26 and the conductors 34, 38 can be sealably attached to one another through adhesive means compatible with the material that the insulative layers 54, 58 are constructed of In alternate embodiments the insulative layers 54, 58 can be applied to the core 26 and the conductors 34, 38 by conformal coating processes, such as, by dipping or spraying, for example.

The terminals 64, 68 can be electrically connected to the conductors 34, 38 either before or after the insulative layers 54, 48 are applied. Processes, such as, soldering, welding and brazing of the terminals 64, 68 to the conductors 34, 38 may be facilitated by doing so prior to application of the layers 54, 58 over the conductors 34, 38. Electrical attachment of the terminals 64, 68 to the conductors 34, 38 after the layers 54, 58 are applied can be done by insulation displacement methods. Regardless of the method of electrical attachment of the terminals 64, 68 to the conductors 34, 38 sealing of the terminals to the layers 54, 58 allows the layers 54, 58 to protect the conductors 34, 38 and the thermoelectric material 30 from fluids and other environmental conditions within which the layered assembly 14 may be submerged.

Referring to FIG. 4, the layered assembly 14 can be heated above a glass transition temperature of the materials employed and then rolled about a perimeter of a die 82 to a desired shape, such, as a cylinder 86, for example, as illustrated in this embodiment. After this forming operation, the layered assembly 14 can be cooled, to a temperature below the glass transition temperature, after which the die 82 may be removed therefrom. The formed layered assembly 14 can then be assembled about the tubular 22 and attached thereto by adhesive, clamping, or wrapping with another material, for example. Alternately, the layered assembly 14 can be formed directly onto the outer surface 18 of the tubular 22 thereby employing the tubular 22 as the die 82 in the forming process directly.

Since, as mentioned above, the thermoelectric material 30 may be extruded, as opposed to being cast, for example, it can be extruded directly into a desired shape, (i.e. the cylinder 86 in the example illustrated). Consequently, the shape of the core 26 of the thermoelectric material 30, as formed, can strongly influence which methods should be employed to bond the conductors 34, 38 and the insulative layers 54, 58 thereto. Regardless of the methods of assembly employed, however, the functioning of the finished borehole tool heat transfer altering system 10 should not be significantly altered.

Referring to FIG. 5, an embodiment of the borehole tool heat transfer altering system 10 disclosed herein is shown employed in a downhole completion 86. The completion 86 includes a tool string 90 having a pump 94 driven by a motor 98. A protector 102 is shown in operable communication with the motor 98 and the pump 94 to among other things equalize pressure between an inside and an outside of the motor 98 while sealing the inside from the outside. The motor 98, in this embodiment, is electrically energized to drive the pump 94 that pumps wellbore fluid 106 from within an annular space 110 defined between the tool string 90 and a wellbore 114. The wellbore fluid 106 may by oil or other hydrocarbons, for example, during production in a hydrocarbon recovery operation.

Electrical energy and friction within the motor 98 during normal operation can cause heating thereof. This increase in temperature can have detrimental effects on the motor 98 itself Systems and methods that decrease the operating temperature of the motor 98 can therefore prolong the life of the motor 98 decreasing downtime of the completion 86 and increasing production in the process. The borehole tool heat transfer altering system 10 attached around the motor 98 serves this function and increases heat transfer from the motor 98 to the fluid 106 surrounding the assembly thereby lowering the operating temperature of the motor 98.

Referring to FIG. 6 the system 10 is employed in alternate completion 116. In this embodiment, instead of the system 10 directly surrounding the motor 98, as it did in the previous embodiment, the system 10 is employed in a radiator 120. The radiator 120 is longitudinally displaced from the motor 98 but is thermally coupled to the motor 98 through a fluid (not shown) that circulates between the motor 98 and the radiator 120 to maintain both the radiator 120 and the motor 98 at nearly the same temperature. As such, by increasing heat transfer between the radiator 120 and the fluid 106, the system 10 is able to increase heat transfer between the motor 98 and the fluid 106 as well.

Referring to FIG. 7 the system 10 is employed in alternate completion 122. As in the previous embodiment this embodiment also employs the radiator 120. The radiator 120 here, however, is positioned longitudinally between the motor 98 and the pump 94. Additionally, the inlets 124 for the fluid 106 to enter the pump 94 are in the radiator 120. This causes the fluid 106 to flow through the radiator 120 before reaching the pump 94. Doing so causes the fluid 106 to increase in temperature as heat from the motor 98 is transferred thereto by the system 10. This increase in temperature of the fluid 106 can cause viscosity of the fluid 106 to decrease which allows it to be pumped more easily thereby increasing operational efficiency of the completion 86.

While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 

1. A borehole tool heat transfer altering system comprising: a borehole tool; and a thermoelectric material in operable communication with the borehole tool configured to alter heat transfer between the borehole tool and an environment surrounding the borehole tool.
 2. The borehole tool heat transfer altering system of claim 1, wherein the alteration of heat transfer causes a cooling of the borehole tool.
 3. The borehole tool heat transfer altering system of claim 1, wherein at least one portion of the borehole tool is tubular and the thermoelectric material is contoured to conform to the at least one portion.
 4. The borehole tool heat transfer altering system of claim 1, further comprising at least two conductors in operable communication with the thermoelectric material.
 5. The borehole tool heat transfer altering system of claim 1, wherein the borehole tool is a motor.
 6. The borehole tool heat transfer altering system of claim 1, wherein the thermoelectric material is disposed at a radiator that alters heat transfer between the borehole tool and an environment.
 7. The borehole tool heat transfer altering system of claim 6, wherein fluid flows through the radiator before entering a pump.
 8. The borehole tool heat transfer altering system of claim 7, wherein the fluid includes oil.
 9. A method of altering heat transfer to a borehole tool, comprising: electrically energizing thermoelectric material in operable communication with a borehole tool and an environment; and altering heat transfer between the borehole tool and the environment.
 10. The method of altering heat transfer to a borehole tool of claim 9, wherein the altering heat transfer between the borehole tool and the environment is a cooling of the borehole tool and a heating of the environment.
 11. The method of altering heat transfer to a borehole tool of claim 9, further comprising positioning the thermoelectric material so that it surrounds the borehole tool.
 12. The method of altering heat transfer to a borehole tool of claim 9, further comprising circulating fluid between a radiator in operable communication with the thermoelectric material and the borehole tool.
 13. A method of heating borehole fluids, comprising: electrically energizing a thermoelectric material; and increasing transfer of heat from a borehole tool to borehole fluids through the thermoelectric material.
 14. The method of heating borehole fluids of claim 13, further comprising generating heat in the borehole tool electrically.
 15. The method of heating borehole fluids of claim 13, further comprising generating heat in the borehole tool frictionally.
 16. A method of increasing efficiency of a borehole pumping operation, comprising: increasing heat transfer between a borehole tool and fluid within a wellbore; decreasing viscosity of the fluid; and pumping the fluid.
 17. The method of increasing efficiency of a borehole pumping operation of claim 16, further comprising heating the fluid. 